Not Applicable.
Not Applicable.
The present invention relates to cellular or wireless call delivery services provided by cellular/PCS operators. Call delivery service permits a cellular or wireless subscriber to receive phone calls either in a home network (e.g., London) or while away from the home network (e.g., in Chicago).
Global Systems for Mobile Communications (GSM) is a widely popular Time Division Multiple Access (TDMA)-based standard used in Europe. TDMA is a digital wireless technology.
A subscriber who roams to Code Division Multiple Access (CDMA) wireless networks may be denied wireless services even if the subscriber""s mobile device is capable of dual-mode (CDMA or analog, and GSM) operation, and the subscriber has the ability to pay for wireless calls with his/her valid credit card. The basis for the denial of service is simply because there is a lack of a GSM Memorandum of Understanding (MoU) between the home GSM network and visited CDMA network for billing settlement.
1. Field of the Invention
The present invention relates to the field of Internet Protocol as used to replace traditional telephony infrastructure for roaming wireless users. The present invention also relates to the field of providing mobile wireless telephone service for users roaming outside their own predefined service area. The present invention also relates to the field of inter-operability of CDMA and GSM/TDMA wireless networks.
2. Description of Related Art
A GSM MoU is an agreement between a consortium of GSM wireless service providers. For example, a subscriber of a first GSM service provider may roam to a service area controlled by a second GSM service provider. An established MoU allows the first GSM service provider to still serve the subscriber while that subscriber is in the service area corresponding to the second GSM service provider. In practice, the second GSM service provider gets paid a portion of the service/roaming charge the first GSM service provider charges the subscriber, which is one reason why wireless xe2x80x9croaming chargesxe2x80x9d are so expensive.
The Local Number Portability (LNP) feature could be used, to some extent, to bypass GSM MoU. LNP allows a telephone subscriber to xe2x80x9cportxe2x80x9d his/her phone number when that subscriber relocates to a different region of the country, even when the local area code may be different (e.g., a subscriber may reallocate from Chicago to New York, but still keep the original phone number used in Chicago which has an area code of 312).
However, LNP updates are not dynamic by design and thus can have serious limitations. A subscriber who wants LNP typically will request that service by filling out a form. The phone company""s administrative staff will manually process the form and make necessary updates of various databases to effect the requested LNP. Note that LNP is designed to support occasional change of location/re-location, and is typically done manually, thus there is a scalability issue in practice.
Public Switched Telephony Network (PSTN) refers to the public phone networks as we know them. PSTN is composed of switches and T1/E1 trunks, central office, etc. PSTN uses circuit-switched technology, in which necessary resources are allocated (dedicated) for the duration of a phone call. An IP network (e.g., the Internet), in contrast, is composed of nodes of computers, serves, routers, and communications links, etc. It employs packet-switching technology which decomposes data (e.g., voice, web pages, an e-mail message) into IP packets. Each packet is then transmitted over an IP network to a destination identified by an IP address and reassembled at the destination. An IP transmission is completed without pre-allocating resources from point to point.
Dynamic Host Configuration Protocol (DHCP) service provides a dynamic IP address with a short term lease. DHCP is covered by RFC 2131. As of the date of this disclosure, RFC 2131 may be obtained from URL http://nic.mil/ftp/rfc/rfc2131.txt. The major use of DHCP is to support dynamic IP address assignment. For example, an ISP (Internet Service Provider) can use DHCP to dynamically assign an IP address to a subscriber after he/she logs in over a dial-up connection; once the session is over, the IP address is recycled for other dial-in users.
Mobile IP is described by Internet Engineering Task Force (IETF) Request for Comments (RFC) number 2002. As of the date of this disclosure, RFC 2002 may be obtained from URL http://nic.mil/ftp/rfc/rfc2002.txt. Unlike H.323, Mobile IP does supports packet mobility, but smooth handoffsxe2x80x94as smooth as circuit cellular voicexe2x80x94are not supported.
The Diffie-Hellman algorithm is a math method allowing two parties to establish a temporary secret for secure transmission of information. This technique is detailed in: Diffie, W. and Hellman, M., xe2x80x9cNew directions in cryptography,xe2x80x9d IEEE Transactions on Information Theory, Vol. IT-22, Nov. 1976, pp. 644-654.
The present invention addresses the above issues of denial of service by combining and integrating the proper pieces of circuit and packet, and that of wireless and wireline. The present invention provides a way to bypass GSM MoU so that GSM users roaming into CDMA networks, having the ability to pay wireless calls with a credit card, can be provided with basic call delivery wireless services.
These and other aspects and attributes of the present invention will be discussed with reference to the following drawings and accompanying specification.